Trees! Planting trees has been a good thing to do for ages, and maybe it’s more important that ever.
Data finally exist to show that if the right species of trees are planted in the right soil types across the planet, the emerging forests could capture 205 gigatons of carbon dioxide in the next 40 to 100 years. That’s two thirds of all the CO2 humans have generated since the industrial revolution. “Forest restoration is by far our most powerful planetary solution today.” scientificamerican.com
There are details, of course. Always details, like the species and soil conditions can make trees better or worse soldiers in the fight against global warming. But a recent study by Tom Crowther, professor of global ecosystem ecology at the Swiss Federal Institute of Technology in Zurich, produced the jaw-dropping numbers quoted above. And Crowther’s study didn’t assume agriculture would be wiped off the face of the planet – we humans can co-exist with all these new trees.
In America, there are many areas where forests are growing back.
The United States went through a period of intense deforestation between 1600 and 1900, but the size of its forest areas has been relatively stable for the last hundred years… between 1990 and 2010, the nation added 7,687,000 hectares (18,995,000 acres) of forested land. The trend in reforesting areas has been driven by organizations such as the U.S. Forest Service and the Arbor Day Foundation. education.seattlepi.com
I’ve also noticed in areas I’ve lived that slopes once cut for firewood are now blanketed in trees. And that’s better than a blanket of carbon dioxide.
Over 100 years ago, a chemist in Kansas documented that cottonwood sap contained methane bubbles. He could light escaping gas and watch a blue flame flicker. Others discovered that not only cottonwoods produce the gas.
Methane is a powerful greenhouse gas and today, thanks to global warming, we need to understand the ins and outs of methane in the atmosphere. New studies show:
Many instances in which trees produce their own methane—sometimes from microbes in the heartwood or other tissues and in other cases from a remarkable direct photochemical reaction thought to be driven by the ultraviolet wavelengths in sunlight. NatGeo
Measuring methane and CO2 emisisons from arctic tundra
Life writes its name with methane, which is why methane on Mars is so exciting. On Earth, methane is released from fossil fuels, microbes in soggy soil like bogs and rice paddies, and (as you know) cattle. Human activities accelerate emissions – sometimes, we do in a year what nature does in centuries.
Methanotroph microbes also break down methane. The life expectancy of an average methane molecule is a few decades.
Trees emit methane and break it down by hosting the wily microbes and also on their own. The balance depends on the tree and soil conditions, but there are “forests where similar trees in similar soils have been measured with a fiftyfold difference in methane emissions… [Forests] in wet soils uniformly were net emitters of methane but those in drier conditions in some regions actually were net absorbers of the gas.”
One scientists said that what we know today is “a third grader’s cartoon drawing of a forest.”
None of this means trees are bad! Trees good. Forests good. But learning more about Earth’s methane cycle will improve our models and, if we’re smart enough, help us hand a beautiful world to our progeny.